1. Field of the Invention
The present invention relates to an encoding device, a decoding device, and printed matter, which can prevent illegitimate falsification/use of coded information.
2. Description of the Related Art
Conventionally, proprietors of supermarkets, convenience stores, and the like, issue coupons as cash vouchers to customers to increase the sale of products. These coupons are collected at the time of payment, when POS (point of sales) terminals and the like obtain information indicating discounted products from the coupons, and deduct predetermined amounts from these products that are targets of the coupons.
However, issuing coupons to customers is a considerably tiresome operation. Japanese Patent Application Laid-open No. 2002-260099 discloses a system that two-dimensionally codes the information indicating the discounted products, transmits this two-dimensionally coded information to mobile telephones and the like belonging to customers, and, at the time of payment, the customers display the two-dimensionally coded information on the screens of their mobile telephones and the like, allowing the POS terminals and the like to read it and deduct predetermined amounts from the discounted products.
However, the two-dimensional code used in Japanese Patent Application Laid-open No. 2002-260099 has a problem in that it is standardized, and can be easily created by a third party. That is, there is a risk that a malicious third party can illegitimately create a two-dimensional code for discounting, and use this to obtain illegitimate discounts on non-discounted products.
The proprietor who issues the two-dimensional code does not assume in many cases that it can be used a plurality of times. However, the two-dimensional code used in Japanese Patent Application Laid-open No. 2002-260099 has no restrictions on its use and can be used unrestrictedly inside the store, leading to a problem that when the same customer uses the same two-dimensional code many times, though sales increase, the intended profit cannot be achieved.